Method Of Converting Shipping Containers To Fluid Tanks

ABSTRACT

A method of constructing a moveable storage tank for the temporary storage of liquids at a fixed location, including the steps of obtaining a moveable shipping container having a bottom section, a top section, two side sections and two end pieces, and removing the end pieces to form a container housing having two end openings. The method further includes installing a shaped floor panel over the bottom section of the container housing to form a reservoir bottom, followed by installing a pair of side panels to the shaped floor panel and two side sections of the container housing to form the reservoir sidewalls. The method also includes the step of installing a pair of bulkheads to the shaped floor panel and the side panels at the two end openings to form a liquid-tight liquids reservoir that is integrated within and substantially conforms to the box-like shape of the container housing.

FIELD OF THE INVENTION

The field of the invention relates generally to moveable liquid storage tanks, and more specifically to moveable frac tanks that provide for the temporary storage of drilling muds and fractionating liquids at wellheads undergoing drilling operations.

BACKGROUND OF THE INVENTION AND RELATED ART

Large, moveable tanks are currently available for the temporary storage and dispensing of liquids, such as fracturing liquids, drilling mud, and the like, for use at an oil or gas well site. Such tanks can also be used for temporarily storing liquids at industrial plants, and for receiving and holding liquids on spills and environmental clean-up jobs until they can be properly disposed of. These moveable tanks are constructed to have a large capacity, typically holding thousands of gallons of liquid. Oftentimes, in circumstances requiring considerable amounts of liquid storage, such as when drilling a well many thousands of feet deep, the resultant network of drilling fluid tanks may require the clearing of a large swath of open area adjacent to the drilling-site to accommodate the tanks, which are typically arranged horizontally over the surface of the ground.

When the empty tanks are no longer needed, they can be transported by truck from one site to another, where they are refilled and reused. As various federal, state and local highway ordinances limit the size of trailers for over-the-road transport, the tanks usually have dimensions conforming to the highway ordinances. In response to a movement in recent years toward larger tanks with greater storage capacity, modern “frac” tanks have evolved into costly, special-purpose tractor-trailer tanks, complete with a rear axle and set of wheels to enable towing of the tanks from one site to another. These special-purpose tanks can include jacking and leveling systems, auxiliary equipment and storage, and custom roof-top configurations for increased foot-purchase when coupled to the back of a tractor rig during transport.

Because of their cost, size and complexity, however, current frac tanks can be difficult to schedule, expensive to transport and lease for an extended period of time (particularly for smaller projects), and difficult to configure or temporarily network with an external piping system.

The present inventor has recognized the need for a more modular and transportable liquid storage or frac tank having a large capacity but which is less expensive to build and operate, is easily transported between locations, and which can provide for a smaller tankage footprint at jobsites.

SUMMARY OF THE INVENTION

The present invention provides a method and system for converting shipping containers into transportable storage tanks for the temporary storage of liquids at a fixed location. The storage tank of the present invention can include a standard ISO or U.S. domestic shipping container with the end pieces removed, forming a generally box-shaped container housing with a bottom section, a top section, two side sections and two end openings. The storage tank can further include a liquids reservoir integrated within the container housing. The liquids reservoir can include a reservoir bottom formed from a shaped floor panel; two reservoir sidewalls formed from a pair of side panels attached to the shaped floor panel, and two reservoir end pieces formed from a pair of bulkheads attached to the floor and side panels at the two end openings of the box-shaped container housing. The reservoir bottom, sidewalls and end pieces can be joined, bonded or welded together to form the liquid-tight liquids reservoir.

The liquids reservoir can provide the storage tank with the capacity to hold a large volume of liquids, while the container housing or shell can facilitate the transportation of the empty tank on an industry-standard truck, railcar or container ship to the job site. The container housing or shell can also provide the corner braces and fittings that allow the tank to be stacked atop (or below) another tank to reduce the tankage footprint at the job site.

The present invention also includes a method of constructing a moveable storage tank for the temporary storage of liquids at a fixed location, which can comprise the steps of obtaining a moveable shipping container having a bottom section, a top section, two side sections and two end pieces, and removing the end pieces to form a container housing having a substantially rectangular cross section and two end openings. The method can further include installing a shaped floor panel over the bottom section of the container housing to form the bottom of the reservoir, followed by installing a pair of side panels to the shaped floor panel and two side sections of the container housing to form the sidewalls of the reservoir. The method can also include the step of installing a pair of bulkheads to the shaped floor panel and the pair of side panels at the two end openings to form the endwalls of the reservoir, and wherein the reservoir bottom, sidewalls and endwalls can be jointed together to form a liquid-tight liquids reservoir that is integrated within the shipping container housing.

The present invention further includes a method of making a transportable frac tank for the temporary storage of well drilling liquids at a fixed location. The method can include the steps of obtaining a shipping container with removed end pieces to form a hollow container shell having a bottom section, a top section, two side sections and two end openings, and installing a shaped reservoir floor over the bottom section of the container housing. The method can further included installing two reservoir sidewalls to the shaped floor panel and two side sections of the container housing, followed by installing two reservoir bulkheads to the reservoir floor and the two reservoir sidewalls to form a liquid-tight frac tank reservoir that is integrated within the outer container shell, resulting in a frac tank that is both transportable on a shipping container transport and stackable during operations at the drilling site.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the invention will be apparent from the detailed description that follows, which taken in conjunction with the accompanying drawings, together illustrate features of the invention. It is understood that these drawings merely depict exemplary embodiments of the present invention and are not, therefore, to be considered limiting of its scope. And furthermore, it will be readily appreciated that the components of the present invention, as generally described and illustrated in the figures herein, could be arranged and designed in a wide variety of different configurations. Nonetheless, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

FIG. 1 a illustrates a perspective view of a common ISO or U.S. domestic shipping container;

FIG. 1 b illustrates a front view of the shipping container of FIG. 1 a;

FIG. 1 c illustrates a back view of the shipping container of FIG. 1 a;

FIG. 2 a illustrates a perspective view of the shipping container of FIG. 1 with the end pieces removed;

FIG. 2 b illustrates a front view of the shipping container of FIG. 2 a;

FIG. 2 c illustrates a back view of the shipping container of FIG. 2 a;

FIG. 3 a illustrates an exploded perspective view of the shaped floor panel and the pair of side panels of the liquids reservoir, according to an exemplary embodiment of the present invention;

FIG. 3 b illustrates an exploded front view of the floor and side panels of FIG. 3 a.

FIG. 4 a illustrates a perspective view of the floor and side panels of FIG. 3 installed in the shipping container housing of FIG. 2;

FIG. 4 b illustrates a front view of the floor and side panels of FIG. 3 installed in the shipping container housing of FIG. 2;

FIG. 5 a illustrates the front view of a bulkhead of the liquids reservoir having an inlet/outlet piping manifold interface, according to an exemplary embodiment of the present invention;

FIG. 5 b illustrates the left side view of the bulkhead of FIG. 5 a;

FIG. 5 c illustrates the right side view of the bulkhead of FIG. 5 a;

FIG. 6 a illustrates the front view of a bulkhead having a clean-out opening and flange, according to another exemplary embodiment of the present invention;

FIG. 6 b illustrates the right side view of the bulkhead of FIG. 6 a;

FIG. 7 a illustrates a perspective view of the bulkheads of FIGS. 5 and 6 installed to the shipping container housing of FIG. 4 to form a liquid-tight frac tank, according to an exemplary embodiment of the present invention;

FIG. 7 b illustrates a front view of the liquid-tight frac tank of FIG. 7 a;

FIG. 7 c illustrates a back view of the liquid-tight frac tank of FIG. 7 a;

FIG. 8 illustrates a top view of a frac tank and piping network, according to an embodiment of the present invention;

FIG. 9 illustrates a perspective view of a frac tank and piping network, according to another embodiment of the present invention;

FIG. 10 is a flowchart depicting a method of constructing a moveable fluid storage tank for the temporary storage of liquids at a fixed location; and

FIG. 11 is a flowchart depicting a method for making a frac tank for the temporary storage of well drilling liquids at a fixed location comprising.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The following detailed description of the invention makes reference to the accompanying drawings, which form a part thereof and in which are shown, by way of illustration, exemplary embodiments in which the invention may be practiced. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that various changes to the invention may be made without departing from the spirit and scope of the present invention. As such, the following more detailed description of the exemplary embodiments of the present invention is not intended to limit the scope of the invention as it is claimed, but is presented for purposes of illustration only: to describe the features and characteristics of the present invention, and to sufficiently enable one skilled in the art to practice the invention. Accordingly, the scope of the present invention is to be defined solely by the appended claims.

The present invention describes methods and systems for converting existing cargo shipping containers into transportable liquid storage tanks for the temporary storage of liquids at fixed locations. More specifically, the method of the present invention can include the conversion of Series 1 General Cargo Freight Containers manufactured according to ISO (International Standards Organization) Standard 668:1995, which defines the external dimensions and ratings for shipping containers in international service. Prior to conversion, the shipping containers can also conform to ISO Standard 1161:1984, which provides the specification for the connection fittings, as well as ISO Standard 1496:1990, which details the manner in which the containers are tested and rated. ISO Standards 668:1995, 1161:1984 and 1496:1990 are each incorporated by reference in their entirety herein. Where applicable, reference herein to these standards is limited to the version of the standards extant at the time of filing the present application.

ISO Standard 668 provides for shipping containers used internationally that are generally 20 ft. or 40 ft. in length, 8 ft. in width, and 8 ft. 6 in. in height. The containers can be structurally designed to be lifted, pushed, pulled and to withstand significant applied forces and accelerations. They can also be designed and rated for stacking atop one other when fully loaded with dry goods, in stacks up to nine containers high. Furthermore, the ISO Series I shipping containers are pre-configured for transportation by truck, rail and container ship, etc., and are provided with fittings that allow for easy connection at the corners of the containers' structural frame to each other and to the mode of transportation. Moreover, an entire world-wide containerization system has been established around manipulating ISO containers, including hoisting from above with cranes, lifting from below with forklifts, fitting within the cargo hold or stacking atop the deck of a container ship, and securely connecting to truck trailers and railroad cars for transportation.

While ISO Standard 668 shipping containers are the most common containers used internationally, the shipping containers used domestically throughout the United States can be larger than the ISO containers, with common dimensions of 45 ft., 48 ft. and 53 ft. in length, 8 ft. 0 in. or 8 ft. 6 in. wide, and 9 ft. 6 in. high. However, even though the exterior dimensions of the U.S. domestic shipping containers can differ significantly from the ISO standard, many other aspects of the ISO standards, such as stackability ratings and corner fitting dimensions, are commonly applied to the U.S. domestic containers. Hence, the methods of the present invention can also include the conversion of U.S. domestic containers into transportable liquid storage tanks for the temporary storage of liquids at a fixed location. Hereinafter and throughout the detailed description, the general terms “container” and “shipping containers” can apply to both ISO containers and U.S. domestic containers, unless specifically identified otherwise.

Due to their plentiful nature, shipping containers have been modified for multiple uses, including offices, mobile hospitals, command and control centers, storage units, outbuildings, structural supports and building blocks for static structures, etc. The containers have also been configured with internal cylindrical vessels conforming to the ASME Boiler and Vessel Code for the transport of pressurized, liquefied gases. However, these containers have not, to date, been successfully adapted for the transportation or storage of liquid cargo. One reason for this deficiency is that the box-shaped structure of the shipping containers generally does not have the lateral strength to hold and constrain a large volume of liquid. Another reason is that liquids can shift and “slop” around within the container during transport; creating unpredictable loading on the transport which could topple the truck or capsize the ship, even if the container itself were well secured.

When converted according to the method of the present invention, however, the shipping containers can provide an excellent framework for constructing a liquid-tight reservoir that substantially conforms to the box-like dimensions of the container, for the temporary storage of liquids at a fixed location. The conversion method of the present invention can include fitting the shipping containers with interior floor and side panels, or insert panels, as well as endwalls or bulkheads complete with an inlet/outlet piping manifold and/or a clean-out interfaces. The result is a liquids reservoir integrated within a shipping container housing or shell that combines the benefits of a large capacity, structurally-sound and liquid-tight storage tank with the advantages of mobility, manipulability and stackability provided by the shipping container.

The present invention provides a number of significant advantages over conventional frac tanks used for on-site storage of drilling liquids. For example, the manifold interface on each tank can facilitate connection of the tank with an external piping system and integration into a network of multiple tanks. By organizing a group of tanks constructed using the various pre-defined container sizes, the user can build a modular liquid tank network that is customizable and configurable for optimal utilization of space at the drilling or industrial site. Furthermore, the ISO standards can allow for tanks built to ISO 668:1995 to be safely stacked two high before being filling with liquids, minimizing the footprint of the tank network. The empty tanks can also be easily manipulated about and re-positioned on the job site using a forklift or crane; and can be transported from site to site using industry-standard trucks and railcars. Containers in accordance with the present invention can also be transported by rail and ship with little difficulty to more remote, international locations, a feature that can be particularly beneficial in international oil and gas drilling operations. Additionally, the plentiful nature of the basic building blocks of the tank, including the shipping container and the steel panels, allows for low-cost production.

Each of the above-recited advantages will be apparent in light of the detailed description set forth below, and will be best understood by reference to the accompanying drawings, wherein the elements and features of the invention are designated by numerals throughout.

With reference to FIGS. 1 and 2, a shipping container 10 is illustrated in accordance with an embodiment of the invention. The underlying support structure of the shipping container 10 is a frame 20 with horizontal beams 22 and vertical beams or corner posts 24, which are connected together at corners fittings 26 to form a box-like shape. The frame 20 of horizontal and vertical beams defines the edges of the shipping container and provides its strength, rigidity and support as it is transported and manipulated about. However, it is the vertical corner posts 24 and corner fittings 26 that serve as the primary load-bearing members when the container is placed or stacked on the ground, on a container ship or on a railroad car. When properly constructed according to ISO standards, the container can serve as the bottom container of an 8-on-1 stack of fully-loaded containers.

Positioned between the horizontal beams 22 and vertical beams 24 are the floor section 32, the side sections 34, the top section 38 and the end pieces 40. The floor section 32 can be reinforced to carry the weight of the cargo, while the end pieces 40 and side panels 34 can be corrugated with vertical stiffening ribs 36 that can serve as secondary load-bearing members to provide additional support to the box-like frame 20 when the container is one of a stack of containers. The top section 38 can be configured as an additional load bearing member.

The corner fittings 26 can be provided with fitting openings 28 (FIG. 1 a) that allow the container 10 to be engaged and manipulated by overhead cranes, specialized container handler forklifts and reach stackers, etc. The fitting openings can also allow for pin-in-slot or twist-cone type connections that removably secure the container to a truck trailer chassis, railroad flatcar, or to each other when stacked.

As shown in FIGS. 1 b and 1 c, the end pieces of the shipping containers can comprise a variety of structures, including but not limited to a pair of doors 42 or a solid endwall 44. Some containers have solid endwalls at both ends and are open-topped without a top section, or have doors in the sidewall 34 (these doors not shown in the figures). Other containers can have doors 42 at both ends for easy loading and unloading. Regardless of the original configuration, however, in the method of the present invention the end pieces 40 and any associated hardware at both ends of the shipping container can be removed, as illustrated in FIGS. 2 a-2 c, leaving a shipping container housing 12 with a bottom section 32, a top section 38, two side sections 34 and two end openings 46.

Combining ISO Standard 668:1995 with the U.S. domestic container industry allows for shipping containers having five common lengths: 20 ft., 40 ft., 45 ft., 48 ft. and 53 ft.; two common widths: 8 ft. 0 in. and 8 ft. 6 in.; and two common heights: 8 ft. 6 in. and 9 ft. 6 in. (high cube). In keeping with the current international and U.S. standards, all dimensions are provided in the original imperial units. The system and method of the present invention is compatible with each size of containers, as well as with many of the variations on the standard shipping container, including the “heavy tested” type containers which are available for heavy goods, such as heavy machinery. It is to be appreciated that the method of the present invention is primarily concerned with the overall box-shaped support structure of the shipping container housing 12, rather than the specific dimensions of the current ISO or U.S. domestic standards. As such, the scope of the present invention can be extended to include variations on the ISO and U.S. domestic standards, such as a conversion from the presently imperial-sized containers to metric-sized containers, or a change in the height-to-width-to-length ratios of the standard container as the containerization industry evolves in response to increased globalization.

Shipping containers can commonly be made from steel, aluminum, wood or plywood and combinations thereof. The structural constraints on the liquid storage tanks of the present invention, however, may require that the shipping container housing 12 generally be formed from metal sheets, either steel or aluminum, of sufficient thickness, strength, and rigidity to contain, together with the reinforcing insert panels of the liquids reservoir, the pressure produced by a column of drilling liquids 8 ft. 6 in. to 9 ft. 6 in. high. As will be described hereinafter, the material of the shipping container housing will also generally be suitable for joining with the insert panels and bulkheads to form an integrated liquids reservoir.

As shown in FIGS. 1 and 2, once the end pieces have been removed from the original ISO shipping container 10, the resulting shipping container housing 12 is ready to receive the insert panels for the liquids reservoir, which are illustrated in FIG. 3. The insert panels can include a shaped floor panel 50 and a pair of side panels 60. The shaped floor panel 50 can have a flattened V-shaped profile (best appreciated from FIG. 4 a) that can include two slightly angled floor pieces 52 that can be joined at a drain groove 54, and which in turn can be connected to two planar and substantially vertical wing pieces 56 which can contact the side sections of the container housing. The two floor pieces 52 can be aligned at a slight angle to form the drain groove 54 so that as the reservoir is emptied, any remaining liquids can be channeled toward a central portion and more easily withdrawn from the tank through an outlet pipe. The floor pieces can be planar sheets or curved sheets, and can extend across the entire width of the container with a minimal amount of elevation increase at the sides, so as to substantially conform to the shape of the container and maximum the volume of the finished reservoir. In the embodiment shown in FIG. 3 b, the rise from the drain groove 54 in the center of the reservoir bottom to the corner joint between the floor pieces 52 and the wing pieces 56 can be about 3 inches.

Although the groove is depicted in the center of the reservoir floor in FIG. 3, it is to be understood that the drawings are provided to illustrate exemplary applications of the invention, and are not to be construed to limit the invention. For example, the drain groove may not be limited to a center location, as the groove may also be located closer to one side of the container housing than the other. In one alternative, a single sloping floor piece can be used locate the drain groove adjacent to one of the side sections, if desired.

As illustrated in both FIGS. 3 and 4, the pair of side panels 60 can be two substantially planar and vertical sidewall pieces 62 that conform to the vertical side sections 34 of the shipping container housing 12, both for combined structural support and to maximum the volume of the completed reservoir. The sidewall pieces 62 can be formed with horizontal triangular stiffening ribs 64 that project inwardly towards the center of the reservoir. As discussed above, the sides of the standard ISO shipping container are often corrugated with vertical ribs 36 to augment the container's load capacity in the vertical direction and increase the container's stack rating for placement near the base of the stack. These vertical structural features, however, are not designed to resist the outward swell of internal pressures that could cause the side sections of the container to bow outwardly. The horizontal stiffening ribs 64 in the side panels 60 can provide the additional strength and rigidity sufficient to resist the outward push of the heavy drilling liquids. In the manufacturing process the sidewall pieces 62 can be folded to create the stiffening ribs 64, or separate stiffening rib segments can be attached to the flat sidewall piece 62 after it has been cut to size. The stiffening ribs 64 can also be orientated in configurations other than horizontal, such as diagonally across the expanse of the sidewall panel from lower corner to opposite upper corner.

FIGS. 4 a and 4 b show the perspective and front views of the shipping container housing 14 with the shaped floor panel 50 installed over the bottom section 32 of the housing to form the floor of the reservoir, and the pair of side panels 60 installed to the shaped floor panel 50 and the side sections 34 of the housing to form the sidewalls of the reservoir.

The floor panel 50 and the side panels 60 can by joined together along seams 58 using a variety of manufacturing techniques suitable for forming a liquid-tight joint, such as welding, tongue-and groove construction and adhesive bonding, bolted flanges with gaskets, etc. In one embodiment of the present invention, however, both the floor panel 50 and the side panels 60 can be made from carbon or high strength, low alloy steel plate or other similar material, having a thickness of about ¼ in. or greater, and can be welded both to each other and to the interior surfaces of the floor section 32, the side sections 34, and the roof section 38 to form liquid tight joints and/or seams.

In another embodiment of the present invention, the floor panel 50 and side panels 60 can be integrally formed or pre-cast from fiberglass, cross-linked polyethylene or other similar composite material, to form a one-piece reservoir liner that can be slidably inserted into the container housing. The composite liner can have a thickness greater than the thickness of alloy steel plate, and can be corrosion resistant and seamless.

Further illustrated in FIG. 4 b is an optional top section support beam 66 for reinforcing the top section of the container housing. The support beam 66 can extend from an upper portion of one of the side panels to an upper portion of the opposite side panel and also attach to the bottom surface of the roof, or top section, of the container housing. If needed, other secondary support beams or braces can also be envisioned within the container housing, without compromising the storage or flow of liquids into and out of the storage tank.

Illustrated in FIG. 5 is one embodiment of a front bulkhead 70 having a cleanout opening 72, stiffening ribs 74, and a piping manifold interface 80 that can be used to connect with an external piping system and allow the completed tank to be integrated into a network with similarly-equipped frac-tanks. As shown, the manifold interface can include suction pipes 82, a gell pipe 84 and a fill pipe 86, with each pipe being equipped with a standard 8-hole flange. It is to be appreciated that other piping and flange configurations can also be included within the spirit and scope of the present invention.

One embodiment of a rear bulkhead 90 is illustrated in FIG. 6. While rear bulkhead 90 could also be equipped with suction, gell and fill pipes to accommodate alternative external piping and tank networks, it can be more economical to provide the rear bulkhead with a simpler configuration having only a cleanout opening 92, stiffening ribs 94 and a drain opening 96 integrated into the cleanout flange cover plate. Regardless of the presence or absence of a manifold interface similar to that shown in FIG. 5, cleanout openings 72 and 92 on both reservoir bulkheads can be aligned with the drain groove located in the V-shaped reservoir floor to provide for a faster and more complete draining of liquids from the tank.

FIG. 7 illustrates the completed tank 16 with a front bulkhead 70 and a rear bulkhead 90 installed at the two end openings to the insert panels 50, 60 previously installed into the container housing 14 (see FIG. 4). The bulkheads can also be attached or welded directly to the perimeter of the two end openings of the container housing, further joining together the internal reservoir structure and the outer container shell. Together, the shaped floor panel 50, the pair of side panels 60 and the pair of bulkheads 70, 90 form a liquid-tight liquids reservoir integrated within and conforming to the box-like shape of the shipping container housing. The completed storage tank 16 is moveable and transportable from site to site when empty, while providing for the efficient and reliable storage of liquids at a fixed location.

Carbon steel or steel alloys can be used for forming the insert panels 50, 60 and bulkheads 70, 90 of the reservoir, as their strength, workability, compatibility with the material forming the shipping container, and their relative low cost in comparison to other materials with similar properties can lead to a more cost-effective tank configuration. However, if the shipping container material is aluminum or other metal alloy which precludes a suitable welded bond with the carbon steel or steel alloys, or if the corrosion characteristics of the liquid intended for storage are incompatible with the more-common steel materials, the insert panels 50, 60 and the bulkheads 70, 90 of the reservoir can be formed from other materials including stainless steel, aluminum alloys, etc. The insert panels and bulkheads of the reservoir can also be treated, coated or painted to form protective coatings over interior or exterior surfaces that prevent corrosion, facilitate cleaning, and/or otherwise improve performance.

In yet another embodiment of the present invention, the floor 50 and side 60 panels and bulkheads (or endwalls) 70, 90 can be integrally formed or pre-cast from fiberglass, cross-linked polyethylene or other similar composite material, to form a one-piece reservoir body that can be slidably inserted into the container housing. The composite reservoir body can have a thickness greater than the thickness of alloy steel plate, and can be corrosion resistant and seamless. Furthermore, openings can be formed and fitted in the end walls, sides, or bottom pieces of the composite reservoir body for the attachment of flanges, cleanouts and valves for connection to other storage tanks or to an external piping system.

Illustrated in FIG. 8 is a top view of the moveable liquid storage tank 16 of the present invention integrated with a plurality of other similar storage tanks 16 into a tank network 18. The tanks can be oriented adjacent to each other and connected through an external piping system, which can include a front side piping section 78 interfaced with the front bulkheads 70, as well as a back side piping section 98 interfaced with the back bulkheads 90. Pumps and valves (not shown) can be included in the external piping system to move the liquids into and out of the storage tanks 16 and through the piping system of the tank network 18.

Also shown in FIG. 8 are access holes 68 formed in the roof section 38 of the storage tank 16 for the cleaning, repair, and maintenance of the internal surfaces of the reservoir.

Referring back to FIG. 7, it is to be appreciated that the completed liquid storage tanks 16 can be stacked atop each other when empty for storage, due to the structural design of the box frame 20 and the corrugated side sections 34 of the original container prior to conversion into a liquid storage tank. As the strength of the container structure is improved by the addition of the reservoir insert panels and the rigid bulkheads 70, 90, it can be further appreciated that the liquid storage tanks 16 can be stacked at least two high and formed into a 3-dimensional tank network prior to being filled with liquids, as the weight of the full upper storage tank can be supported by the vertical corner posts and corner fittings of the lower storage tank. This is advantageous over the frac-tanks of the prior art, which can require large swaths of open areas to be cleared next to the drilling-site to accommodate the horizontally-arranged fluid tanks. By providing for stackable frac tanks, the required ground surface area adjacent the drilling site needed for tankage can be greatly reduced.

An example of a 3-dimensional tank network with frac tanks stacked at least two-high for forming a frac tank and piping network 100 is illustrated in FIG. 9, according to another embodiment of the present invention. The frac tank and piping network 100 can include multiple moveable liquid storage tanks 110 as described above, which can be stacked two-high and structurally supported by the horizontal 122 and vertical 124 support beams and connected together at the corner fittings 126. The network of moveable liquid storage tanks can be fluidly connected with an external piping manifold system with inlet and outlet piping attached to the front or rear bulkheads of the frac tank (as previously discussed), or through internal piping 130, 140 which can fluidly couple the storage tanks from top-to-bottom and/or side-to-side, as shown in FIG. 9. In one aspect of the present invention, the internal piping 130 which fluidly couples an upper tank 114 to a lower tank 112 is a straight pipe connection 136 with an upper portion 134 in the floor panel and bottom section of the upper tank, and a lower portion 132 in the roof section of the lower tank. The straight pipe connection 136 may or may not included a control valve for isolating the upper tank from the lower tank.

In another aspect of the present invention 100, the internal piping 140 fluidly coupling two horizontally-adjacent moveable liquid storage tanks 116, 118 can include a series of sealed pipes 142 passing laterally through the internal volume of the liquid tanks 110 and connecting through the sidewalls of the tanks and side sections of the containers. The internal pipe 142 can include an inlet/outlet port 144, which can allow fluid inside the tank to flow into the pipe, or fluid in the pipe to flow out into the tank. The inlet/outlet ports 144 may or may not include a valve. Valves may also be located in the internal pipes at the junctions 146 between the two adjacent container housings, so that the liquid storage tanks can be isolated and drained or filled separately.

FIG. 10 is a flowchart depicting a method 150 of constructing a moveable storage tank for the temporary storage of liquids at a fixed location, according to an exemplary embodiment of the present invention. The method can including the steps of obtaining 152 a moveable shipping container having a bottom section, a top section, two side sections and two end pieces, and removing 154 the end pieces to form a container housing having a box-like shape and two end openings. With the container housing in hand, the method can further include the operations of installing 156 a shaped floor panel over the bottom section of the container housing to form the bottom of the reservoir, followed by installing 158 a pair of side panels to the shaped floor panel and side sections of the container housing to form the two sidewalls of the reservoir. The method can also include the step of installing 160 a pair of bulkheads to the shaped floor panel and side panels at the two end openings to form the two endwalls of the reservoir, and wherein the reservoir bottom, sidewalls and endwalls can be joined together to form a liquid-tight liquids reservoir that is integrated within the shipping container housing.

In an alternative embodiment, it can be appreciated that the insert pieces, including the shaped floor panel and the pair of sidewall panels, can be pre-assembled separate from the container housing and then inserted as one piece into the housing. Although it may be unwieldy to slide one large 20 ft., 40 ft. or longer insert piece into the container housing, the benefits of pre-assembling the separate insert pieces in a controlled environment and with access to both sides of the seams or joints may result in a stronger insert piece with advantages that outweigh the increased difficulty in putting the reservoir together.

Likewise, it can further be appreciated that installing smaller sections of the insert pieces into the container housing, or shorter combined floor/sidewalls segments that result in a series of assembly welds that are transverse, rather than parallel, to the long axis of the container housing, can also be considered to fall within the scope of the present invention.

Further illustrated in FIG. 11 is a flowchart depicting a method 170 making a transportable frac tank for the temporary storage of well drilling liquids at a fixed location, according to another exemplary embodiment of the present invention. The method 170 includes the step of obtaining 172 a shipping container with removed end pieces to form a container housing having a box-like shape with a bottom section, a top section, two side sections and two end openings. The method can further include the operations of installing 174 a shaped reservoir floor over the bottom section of the container housing, and installing 176 two reservoir sidewalls to the shaped floor panel and two side sections of the container housing. After the floor and sidewalls have been installed into the container housing, the method can also include installing 178 two reservoir bulkheads to the reservoir floor and sidewalls to form a liquid-tight frac tank reservoir that is integrated within the container housing shell, allowing the frac tank to be transportable on a shipping container transport.

The foregoing detailed description describes the invention with reference to specific exemplary embodiments. However, it will be appreciated that various modifications and changes can be made without departing from the scope of the present invention as set forth in the appended claims. The detailed description and accompanying drawings are to be regarded as merely illustrative, rather than as restrictive, and all such modifications or changes, if any, are intended to fall within the scope of the present invention as described and set forth herein.

More specifically, while illustrative exemplary embodiments of the invention have been described herein, the present invention is not limited to these embodiments, but includes any and all embodiments having modifications, omissions, combinations (e.g., of aspects across various embodiments), adaptations and/or alterations as would be appreciated by those in the art based on the foregoing detailed description. The limitations in the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the foregoing detailed description or during the prosecution of the application, which examples are to be construed as non-exclusive. For example, in the present disclosure, the term “preferably” is non-exclusive where it is intended to mean “preferably, but not limited to.” Any steps recited in any method or process claims may be executed in any order and are not limited to the order presented in the claims. Means-plus-function or step-plus-function limitations will only be employed where for a specific claim limitation all of the following conditions are present in that limitation: a) “means for” or “step for” is expressly recited; and b) a corresponding function is expressly recited. The structure, material or acts that support the means-plus function are expressly recited in the description herein. Accordingly, the scope of the invention should be determined solely by the appended claims and their legal equivalents, rather than by the descriptions and examples given above. 

1. A method of constructing a moveable storage tank for the temporary storage of liquids at a fixed location comprising: obtaining a moveable shipping container having a bottom section, a top section, two side sections and two end pieces; removing the two end pieces to form a container housing having two end openings; installing a shaped floor panel over the bottom section of the container housing to form a reservoir bottom; installing a pair of side panels adjacent the shaped floor panel and the side sections of the container housing to form two reservoir sidewalls; and installing a pair of bulkheads to the shaped floor panel and the pair of side panels at the two end openings to form two reservoir endwalls, wherein the reservoir bottom, sidewalls and endwalls combine to form a liquid-tight liquids reservoir integrated within the moveable container housing.
 2. The method of claim 1, further comprising configuring the outside of the shaped floor panel, the pair of side panels and the pair of bulkheads to substantially conform to the inside of the container housing.
 3. The method of claim 1, further comprising reinforcing the container housing in a manner sufficient to support a second container housing stacked atop the moveable storage tank and fillable with liquids.
 4. A method of forming a frac tank for the temporary storage of well drilling liquids at a fixed location comprising: obtaining a shipping container with removed end pieces to form a container housing having a bottom section, a top section, two side sections and two end openings; installing a shaped reservoir floor over the bottom section of the container housing; installing two reservoir sidewalls adjacent the shaped floor panel and two side sections of the container housing; installing two reservoir bulkheads adjacent the reservoir floor and the two reservoir sidewalls to form a liquid-tight frac tank reservoir integrated within the container housing, the frac tank being thereby transportable on a shipping container transport.
 5. The method of claim 4, further comprising configuring the outside of the shaped floor panel, the pair of side panels and the pair of bulkheads to substantially conform to the inside of the container housing.
 6. The method of claim 4, further comprising reinforcing the container housing in a manner sufficient to support a second container housing stacked atop the moveable storage tank and fillable with liquids.
 7. A transportable storage tank for the temporary storage of liquids at a fixed location comprising: a shipping container housing having a generally box-like shape with a bottom section, a top section, two side sections and two end openings; and a liquids reservoir integrated within the shipping container housing, the liquids reservoir further comprising: a reservoir bottom formed from a shaped floor panel installed over the bottom section of the container housing; two reservoir sidewalls formed from a pair of side panels attached to the shaped floor panel and two side sections of the container housing; two reservoir end pieces formed from a pair of bulkheads attached to the shaped floor panel and the pair of side panels at the two end openings, wherein the reservoir bottom, the reservoir sidewalls and the reservoir end pieces join together to form a liquid-tight liquids reservoir.
 8. The storage tank of claim 7, wherein the liquids reservoir substantially conforms to the box-like shape of the container housing.
 9. The storage tank of claim 7, wherein the shipping container housing is made from a Series 1 General Cargo Freight Container manufactured to ISO Standard 668, effective as of the filing date hereof.
 10. The storage tank of claim 7, wherein the tank is transportable on a shipping container transport.
 11. The storage tank of claim 7, wherein the tank can be loaded and unloaded from the shipping container transport with a forklift.
 12. The storage tank of claim 7, wherein the tank can be loaded and unloaded from a tilt-bed shipping container transport.
 13. The storage tank of claim 7, wherein the tank is stackable atop another transportable fluid storage tank.
 14. The storage tank of claim 7, wherein the reservoir bottom, the two reservoir sidewalls and the two reservoir end pieces are formed from steel alloy plate having a thickness of at least about 0.25 inches.
 15. The storage tank of claim 7, wherein the reservoir bottom, the two reservoir sidewalls and the two reservoir end pieces are welded to each other and to the container housing to form substantially liquid-tight joints.
 16. The storage tank of claim 7, wherein the shaped floor panel further comprises a flattened V-shaped floor panel with a groove configured for channeling fluid.
 17. The storage tank of claim 16, further comprising a cleanout flange formed in at least one of the pair of bulkheads and in line with the central groove of the V-shaped floor panel.
 18. The storage tank of claim 7, further comprising a manifold system formed in at least one of the pair of bulkheads configured for conveying fluid into and out of the storage tank.
 19. The storage tank of claim 7, wherein the two reservoir sidewalls further comprise side panels having stiffening ribs associated therewith.
 20. The storage tank of claim 19, wherein the stiffening ribs are horizontal.
 21. The storage tank of claim 7, further comprising access ports formed in the top section of the container housing, the access ports being operable to allow for the cleaning, repair, and maintenance of the internal surfaces of the reservoir.
 22. The storage tank of claim 7, further comprising at least one support beam extending from an upper portion of one of the two reservoir sidewalls to an upper portion of an other reservoir sidewall, and wherein the support beam is coupled to the top section of the container housing. 